viii THE ESSENTIALS OF AGRICULTURE 



Professor of Farm Crops, University of Missouri ; C. A. Mooers, 

 Chemist and Agronomist, University of Tennessee; A. H. 

 Leidigh, Agronomist in Charge of Soils, Texas Agricultural 

 College; C. B. Williams, Chief of Division of Agronomy, North 

 Carolina Agricultural College ; Dr. A. N. Hume, Agronomist, 

 South Dakota State College; J. A. Foord, Professor of Farm 

 Administration, Massachusetts Agricultural College; and C. F. 

 Marbut, Director of the Soil Survey, United States Bureau 

 of Soils. 



The author also desires to express his profound gratitude to 

 J. W. Searson, Professor of the English Language, of the Kansas 

 State Agricultural College, for general advice and for assistance 

 in the arrangement of subject matter, and to E. L. Holton, Pro- 

 fessor of Education, H. L. Kent, Professor of Vocational Edu- 

 cation, and J. H. Miller, Dean of the Extension Division, of 

 the Kansas State Agricultural College, for helpful criticisms. 



Especial acknowledgment is due Dr. Otis W. Caldwell, Dean 

 of the University College and Professor of Botany in the School 

 of Education of The University of Chicago -and a recognized 

 authority in matters pertaining to the teaching of science, for 

 his constructive criticisms of the entire manuscript and for his 

 invaluable assistance in editing and adapting the work to the 

 needs of secondary schools. 



HENRY JACKSON WATERS 



